Ecological drivers of plant diversity patterns in remnants coastal sand dune ecosystems along the northern Adriatic coastline

Coastal sand dunes represent one of the most fragile ecosystems in the Mediterranean basin. These habitats naturally suffer the action of several limiting factors such as sand burial, marine aerosol and low soil fertility; on the other hand, they often host species of high conservation value. Over the last decades, they have also experienced a high level of biological invasion. In this study, we sampled psammophilous vegetation in two sites in the northern Adriatic coast belonging to the Natura 2000 network to describe diversity patterns and to identify the main ecological drivers of species diversity. Plant species richness and their abundance were assessed in each plot. Differences in species composition for native and alien species were compared via PERMANOVA analysis. Species complementarity was explored by partitioning beta diversity in its spatial components (richness and replacement). A Generalized Linear Model was also computed to assess the main environmental factors that may promote invasiveness in these ecosystems. For the investigated area, our results highlight the strong differentiation in community composition both in alien and native species: in particular alien species showed on average a lower complementarity among habitats compared to native species. Specifically, communities seem to be more diversified when larger spatial scales were considered. Beta diversity in both groups appears to be more dominated by the richness component with respect to the replacement component. Furthermore, in these habitats, the occurrence of alien species was shown to be related to geomorphological predictors more than climatic variables

Lightning strikes: rethinking the nexus between Australian Indigenous land management and natural forces

Research in the 1960s and 1970s by Merrilees, Hallam and Jones brought to prominence the concept that ‘fire-stick’ farming shaped the Australian environment creating small-scale mosaic vegetation patterns such that the productive capacity increased and that grasslands with spaced trees were maintained, a ‘caring for country’. Signs of fire during the colonial period (1788–1901) have been interpreted as expressions of Aboriginal ‘caring for country’. Close examination of other kinds of cultural causes for fire and smoke, as well as an assessment based upon bushfire incidents in south-eastern and south-western Australia, suggests there is a likelihood that at least some, if not the majority, of the ignitions attributed to Aboriginal agency were caused by lightning strikes. A brief case study of the Jingera Rocks wildfire, inland from Bega, south-eastern New South Wales, and in close proximity to lands described by Weatherhead in a colonial narrative, is provided to illustrate the impact of lightning that strikes in mountainous and distant locations. A comparative study of colonial period and contemporary Western Australia wildfire incidents highlights the discrepancies in fit between the reality of today, an understanding of Aboriginal caring for country and fire behaviour attributed to lightning ignitions. The implications for researchers are apparent in that they no longer can rely upon generalised interpretations of the colonial record but must validate assumptions concerning the use of fire by Aboriginal people and be particularly careful when those notions are applied to guide contemporary fire management practices.</p